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Assessing pesticide concentrations and fluxes in the stream of a small vineyard catchment - Effect of sampling frequency
2010
Rabiet, M. | Morgoum, C. | Gouy, V. | Carluer, N. | Coquery, M.
This study reports on the occurrence and behaviour of six pesticides and one metabolite in a small stream draining a vineyard catchment. Base flow and flood events were monitored in order to assess the variability of pesticide concentrations according to the season and to evaluate the role of sampling frequency on the evaluation of fluxes estimates. Results showed that dissolved pesticide concentrations displayed a strong temporal and spatial variability. A large mobilisation of pesticides was observed during floods, with total dissolved pesticide fluxes per event ranging from 5.7 × 10−3 g/Ha to 0.34 g/Ha. These results highlight the major role of floods in the transport of pesticides in this small stream which contributed to more than 89% of the total load of diuron during August 2007. The evaluation of pesticide loads using different sampling strategies and method calculation, showed that grab sampling largely underestimated pesticide concentrations and fluxes transiting through the stream. This work brings new insights about the fluxes of pesticides in surface water of a vineyard catchment, notably during flood events.
Afficher plus [+] Moins [-]Assessment of the emission of PCDD/Fs and dioxin-like PCBs from an industrial area over a nearby town using a selective wind direction sampling device
2010
Martínez, Karell | Austrui, Joan Rivera | Jover, Eric | Ábalos, Manuela | Rivera, Josep | Abad, Esteban
The development of new sampling devices or strategies to assess the concentration of persistent organic pollutants (POPs) in the environment has increased in the last two decades. In this study, a selective sampling device was used to evaluate the impact of potential local sources of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/Fs) and dioxin-like polychlorinated biphenyl (dl-PCBs) emissions on the ambient air levels of such compounds in a town near an important industrial estate. Average concentrations of target compounds of up to 2.5 times for PCDD/Fs and 2 times for dl-PCBs were found to come from the industrial state confirming this area as the main responsible for the majority of such compounds reaching the town. This finding was supported by a PCDD/F and dl-PCB sample profile analysis and a principal component analysis (PCA), which established a direct link between the dioxin-like compounds found in the samples collected in the town and their source. Selective ambient air samplers provide a valuable information on POP emission sources.
Afficher plus [+] Moins [-]The impact of wood smoke on ambient PM2.5 in northern Rocky Mountain valley communities
2010
Ward, Tony | Lange, Todd
During the winters of 2006/2007 and 2007/2008, PM2.5 source apportionment programs were carried out within five western Montana valley communities. Filter samples were analyzed for mass and chemical composition. Information was utilized in a Chemical Mass Balance (CMB) computer model to apportion the sources of PM2.5. Results showed that wood smoke (likely residential woodstoves) was the major source of PM2.5 in each of the communities, contributing from 56% to 77% of the measured wintertime PM2.5. Results of 14C analyses showed that between 44% and 76% of the measured PM2.5 came from a new carbon (wood smoke) source, confirming the results of the CMB modeling. In summary, the CMB model results, coupled with the 14C results, support that wood smoke is the major contributor to the overall PM2.5 mass in these rural, northern Rocky Mountain airsheds throughout the winter months. This manuscript describes how woodsmoke is the largest source of PM2.5 in the Northern Rocky Mountains of the US.
Afficher plus [+] Moins [-]Determination and Evaluation of Sampling Velocity in a Simple Passive Sampling Method to Monitor HNO₃(g) in Ambient Air
2010
Aikawa, Masahide | Nishikawa, Yoshinori | Yamagami, Makiko | Hiraki, Takatoshi | Murano, Kentaro | Mukai, Hitoshi
We evaluated the applicability of a simple passive sampling method to quantify HNO₃(g) in ambient air. The method has the advantages of not only ease of operation but also low cost. A sampling velocity of 214 m day⁻¹ was determined based on the concentration of HNO₃(g) measured by the four-stage filter-pack method at nine sites located within a 250 × 250-km area in Japan. This sampling velocity was applied at sites located outside of area to verify the applicability and accuracy of the simple passive sampling method. The variation in the results for the application of the sampling velocity ranged from 0.39 to 0.95. The simple passive sampling method should be applied to sites with different meteorological conditions, and the obtained data should be used to obtain more significant information and/or to indicate the need for further developments in the methodology.
Afficher plus [+] Moins [-]Biological and Artificial Matrixes as PAH Accumulators: An Experimental Comparative Study
2010
Skert, Nicola | Falomo, Jari | Giorgini, Luigi | Acquavita, Alessandro | Capriglia, Lorenzo | Grahonja, Roberto | Miani, Nordio
In order to find out a new effective accumulator of polycyclic aromatic hydrocarbons (PAHs) useful for monitoring studies on a large scale and low costs, the accumulation capacity of both biological and artificial matrixes (mosses and polyester fibers, respectively) has been tested. For this purposes, Hypnum cupressiforme and dacron® were exposed to pollution airborne in two sites located nearby an active iron industry and in center of the town of Trieste, where high PAH pollution spots, due to vehicular traffic, are usually detected. The samplers were exposed in six sampling sessions for 21 days. The results obtained were compared with data collected by active PAH samplers, usually employed for official widespread monitoring. The level of correlation between the data sets was calculated. Furthermore, a repeatability study of data was performed. According to the results, both matrixes are good PAH accumulators, though they show different skills.
Afficher plus [+] Moins [-]Ozone and Nitrogen Dioxide Levels Monitored in an Urban Area (Ciudad Real) in central-southern Spain
2010
Martin, Pilar | Cabañas, Beatriz | Villanueva, Florentina | Gallego, Maria Paz | Colmenar, Inmaculada | Salgado, Sagrario
This work describes the evolution of NO₂ and O₃ levels from January to December of 2007, covering the four seasonal periods in the urban air of Ciudad Real in the central-southern Spain. The measurements were carried out by means of passive samplers (Radiello® samplers). Eleven samples were collected weekly, placed at different monitoring site locations. The data indicate that the mean levels obtained during this period for O₃ and NO₂ were 38.5 ± 3.5 and 20.8 ± 3.8 μg/m³, respectively. These measurements were compared with other studies in Ciudad Real. Meteorological conditions (temperature, pressure, humidity relative, wind speed and direction) were also investigated.
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